Self-locking chuck



y 1949- H. L. PROCTOR 2,470,720

SELF-LOCKING cnucx Filed May 31, 1947 2 Sheets-Sheet 1 is x Patented May17, 1949 .Harry vIi. Proctor- Logansporh Ind; assignor toLoganspcrtMachine C0. Inc.,- Lganspo1-t,.Ind,

a corporation of- Indiana 1 Appl'icatiohlMay 31,;1947;-.'Serial1No.i7.51,515

I 13Glaims. 1

My invention relates todmprovements in self locking chucks.Chucks-forh'olding work in place to-perform a turning operation-are wellknown. 'They are actuated -mechanically, hydraulically, pneumaticallyand electrically- Dneof the serious problems is'toiinsure thatthe: chuckwill hold the work at high speed without the possibility of the chuckjaws moving outwarddue t0 centriiugaL force andreleasing the work, eventhough the power, whatever it maybep-whicl' a'ctuates the chuck jaws-andnormally-holds them in" work gripping position, may fall. Myselflockingchuck. may be'opened and closed under the control of the operator butautomatically and permanently remain i closed-after it gripped the workuntil the operator-actually manipulates it for release.

My invention is'illustratedmore or'-1ess"diagrammatically in theacccmpanyingdrawings wherein:

Figure 1 is a frontelevation, with -parts .cut away;

Figure 2 is a partsectionalongtheline-Z- -Z- of Figure 1.

Like parts are indicatedby like symbols; throughout the specificationand drawings.

1' is a chuck housing Itis recessedatdeto engage and be mounted on anysuitable lathe spindle not here iil-l'ustratedi 3--indicates -fichethree 'm'aster jaws of the chuck. T-hey are mov-- able,r'adi'ally towardand fromthe centeroi rotation. 4 are false jaws attached to each of -themaster jaws 3 designedto fit the work-piece. They'are held in positionbyremovabl-e screws 5 threaded in the master jaws 3. 6 isthe draw; studactuated by mechanical, electricali-s-pneum'atic or hydraulic 11163115935 the-case-may: be, not here illustrated. 'The draw stud has ahead Iand is threaded to be engaged by-nuts (Land 9 locked one against theother.-- H is a flanged-t lock release sleeve on the draw studs -l2isthe lock sleeve'washer. J3 is-the-draw stud collar threaded in thedrawsleeve' l l'. I-he lock -release sleeve II and the locksleevewasherr t2 are held in a fixed positionon the draw-studEk-between. the head I and the nut 8 andisslidable and rotatable inthedraw stud collar l3, i4 is the drawsleeve which is slidableinthecentral bore-2am the chuck housing 1. 1'5 is thejawactuating lever.There are three ofthem; one forweach-r master jaw 3/ Each lever. ismounted on a pivot it supported in the chuck housing in t1 isa iaw blockslidable in the chuck jaw '2 in a' direction parallel with the axis ofrotation of ,the' chuck, being closely fitted. in theiap'erture' I8against radial'movement. 'The jaw-(block H is pivoted to one endoitheleverl5 at=l9. .29 is the-drawsleeve block. socketed in. the aperture 2I inthe drawsleeve 14-, so as to .permit radial .mevementandprevent-ax-ial movement of=the block with respect to =the drawsleeveM. The leverliand the draw sleeve block 2B arepivoted together: at 22.23 is a-central bore-in :the chuck housing l parallel with the axis ofthe draw stud fi. .-Sliding inhthis-lboredd is.\thedrawsleeve- M-havinga tapered locking shoe 2A- oppositeeach masterjaw 3. The lockingshoe 24 increases in thickness toward the front of the chuckand mateswith a similar locking tape-red surface .25. cut. as a-lseyway in. the idrawsleeve it. Locking shoe 24 has a -headili. engaged by a shce tensionspring 27 which-at-theoppdsite end abuts on a --shoulder 28 insthe=drawsleeve We. The chuck end of the drawsleeva l4 is-counter-bored toprovide a sliding fit over the inwardlyextended portion of the pilotbushing'ZB. Pilot bushing 29 is-also outwardly flanged at 30 to make asliding fit with theinner endofi-the master jaws 3, both jointsproviding a.dirt-seal. This pilot bushing 29 is recessed into the chuckhousing i and held there by screws 3 I .The useand-operat-ion of myinvention: are as follows:

'IThe chuck is mounted on the iace'plateor spindle of the lathe in theusual-manner. The draw stud is connected to the draw stud operatingmechanism which might be a mechanical member, aihydraulic orpneumatic-piston, or v an'electromagnet or solenoid. With the parts asshown iitFigure 2,,the-fa-lse jaw'being in place, the work is. presentedtothe chuck and the. operator causes thedrawv stud to move to the left.-The draw sleeve- M comes with it and moves the inner end of .each oi-thelevers 5. toward the left. This causes. the outerhendof -the levers-l5to move radially inward carrying with -them the master jaws 3 and thefalse jaws '4' to grip thework.

Under these circumstances, if the lathe starts tolturn and somethinggoes wrong withthe draw baractuating mechanism, centrifugal iorce willcause the masterjaws and theifalsejaws to move radially outward to.release the -.work.= I to avoidthis that nay-invention has heenmade.

As the draw sleeve l4 ismovedlto the left by the draw stud, itcompressesthe-shoe tension spring 2l.andlcauses. the lockingshoaZd to: move t6 theleft with-.th'e draw .sleeve Mthusmaintainingthe tapered surface's 25-ion locking shoe anddraw? sleeve ..together. If tension 5 ion the. drawstud. 6 should fail, -centrifugal- ;;force applied to thenmasterajaws v3and ialse jaws 5 would tend to rotate the lever it] about its pivotpoint It, the jaws tending to move the block I! outwardly. This actionwould tend to move the draw sleeve It in the chuck opening direction orto the right. However, this is resisted by the presence of the lockingshoe and any tendency on the part of the draw sleeve Iii to move to theright merely causes it to try to slide up on the locking taper thuslocking the draw sleeve more firmly in position. So a mere failure onthe part of the draw stud holding means will not cause chuck release.

The chuck can be released, however, when the draw stud ii moves to theright. Under these circumstances the lock release sleeve l I will moveto the right, the lock sleeve washer l2 will thus be taken out ofcontact with the draw stud collar l3 and the draw stud collar l3 willremain at rest with the chuck still locked until the flange at the innerend of the lock release sleeve ll engages the opposed face of the drawstud collar I3, tending to move it to the right. But it cannot move tothe right unless the locking shoe moves at the same time so the lug 26on the looking shoe M- is also engaged by the flange on the lock releasesleeve ii, and under these circumstances the locking shoe 24 and thedraw sleeve M may both move in unison to the right to cause the leversl5 to rotate about their pivot l6 and move the master jaws 3 radiallyoutward, and this movement can continue until the maximum open positionhas been reached and the work is released.

It will be realized that, whereas, I have described and illustrated apractical and operative device, nevertheless many changes may be made inthe size, shape, number and disposition of parts without departing fromthe spirit of my invention. I therefore wish my description and drawingsto be taken as in a broad sense illustrative or diagrammatic, ratherthan as limiting me to my precise showing.

I claim:

1. In a chuck, a draw sleeve and. a locking shoe, having opposedinclined locking surfaces, means engaging the sleeve alone to move it injaw closing direction, a spring between the shoe and the sleeve adaptedto hold the surfaces together and cause the shoe to follow the sleeve insuch movement, means engaging the sleeve and the shoe to move themtogether in the jaw opening direction.

2. In a chuck, a housing, a draw sleeve mounted for axial movement andchuck jaws mounted for radial movement therein, actuating levers betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, the draw sleeve having a draw stud collar,a lock release sleeve in slidable engagement with the draw stud collar,flanged at one end and having a washer at the other end, the spacebetween the flange and the washer being greater than the axial length ofthe draw stud collar, a locking shoe slidable in the chuck housing,opposed surfaces of the shoe and the sleeve being inclined to the axisof the chuck, a spring interposed between the shoe and the draw sleevetending to draw the inclined locking surfaces of shoe and draw sleevetogether.

3. In a chuck, a housing, a draw sleeve mounted for axial movement andchuck jaws mounted for radial movement therein, actuating levers betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, the draw sleeve having a draw stud collar,a lock release sleeve in slidable engage- .4 ment with the draw studcollar, flanged at one end and having a washer at the other end, thespace between the flange and the washer being greater than the axiallength of the draw stud collar, a locking shoe slidable in the chuckhousing, opposed surfaces of the shoe and the sleeve being inclined tothe axis of the chuck, a spring interposed between the shoe and the drawsleeve tending to draw the inclined locking surfaces of shoe and drawsleeve together, a draw stud on which the lock release sleeve ismounted, the lock sleeve washer being adapted to engage the draw studcollar only to move the draw sleeve under tension from the draw stud inchuck jaw closing position.

4. In a chuck, a housing, a draw sleeve mounted for axial movement andchuck jaws mounted for radial movement therein, actuating levers betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, the draw sleeve having a draw stud collar,a lock release sleeve in slidable engagement with the draw stud collar,flanged at one end and having a washer at the other end, the spacebetween the flange and the washer being greater than the axial length ofthe draw stud collar, a locking shoe slidable in the chuck housing,opposed surfaces of the shoe and the sleeve being inclined to the axisof the chuck, a spring interposed between the shoe and the draw sleevetending to draw the inclined locking surfaces of shoe and draw sleevetogether, a draw stud onwhich the lock release sleeve is mounted, thelock sleeve washer being adapted to engage the draw stud collar only tomove the draw sleeve under tension from the draw stud in chuck jawclosing position, the collar on the lock release sleeve being adaptedwhen the draw stud is moved in the opposite direction to engage both theshoe and the draw stud collar to move them both in unison in the jawopening direction.

5. In a chuck, a housing, a draw sleeve mounted for axial movement, andchuck jaws mounted for radial movement therein, actuating means betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws means for displacing the sleeve axially toclose the chuck jaws, means interposed between the housing and thesleeve for automatically locking the sleeve against jaw release movementby centrifugal force.

6. In a chuck, a housing, a draw sleeve mounted for axial movement, andchuck jaws mounted for radial movement therein, actuating means betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, means interposed between the housing andthe sleeve for locking the sleeve against jaw release movement, saidlooking means including a tapered locking shoe and yielding means forholding it in locking engagement with the sleeve.

7. In a chuck, a housing, a draw sleeve mounted for axial movement, andchuck jaws mounted for radial movement therein, actuating means betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws means for displacing the sleeve axially toclose the chuck jaws, means interposed between the housing and thesleeve for automatically locking the sleeve against jaw releasemovement, means adapted to engage the sleeve alone for moving it intojaw locking position.

8. In a chuck, a housing, a draw sleeve mounted for axial movement, andchuck jaws mounted for radial movement therein, actuating means betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, means interposed between the housing andthe sleeve for locking the sleeve against jaw release movement, saidlocking means including a tapered locking shoe and yielding means forholding it in locking engagement with the sleeve and means adapted toengage the sleeve along for moving it into jaw locking position.

9. In a chuck, a housing, a draw sleeve mounted for axial movement, andchuck jaws mounted for radial movement therein, actuating means betweenthe sleeve and the jaws whereby axial movement of the sleeve impartsradial movement to the jaws, means interposed between the housing andthe sleeve for locking the sleeve against jaw release movement, meansadapted to engage the sleeve alone for moving it into jaw lockingposition, and said means being adapted to engage both the sleeve and thelocking means to move them into jaw releasing position.

10. In a, chuck, a housing, a draw sleeve mount ed for axial movement,and chuck jaws mounted for radial movement therein, actuating meansbetween the sleeve and the jaws whereby axial movement of the sleeveimparts radial movement to the jaws, means interposed between thehousing and the sleeve for locking the sleeve against jaw releasemovement, said locking means including a tapered locking shoe andyielding means for holding it in locking engagement with the sleeve andmeans adapted to engage the sleeve alone for moving it into jaw lockingposition, and said means being adapted to engage both the sleeve and theshoe to move them into jaw releasing position.

11. In a chuck, a draw sleeve, a draw stud associated therewith, alocking shoe in engagement with the draw sleeve, sleeve and shoe havinginclined oppositely engaged locking surfaces, a spring interposedbetween the shoe and the sleeve adapted to hold said surfaces together,means for moving the sleeve in jaw closing direction whereby the springcauses the shoe to the draw sleeve and the housing, a spring between thesleeve and the shoe adapted to hold the shoe in sleeve locking position,means for moving the stud in one direction to move the draw sleeve sothat it rotates the levers to clamp the jaws, means for moving the studin the opposite direction for a predetermined distance without movementof the draw sleeves and for thereafter causing the stud as it continuesits movement to overcome the spring pressure and move the draw sleeveand the locking shoes in unison toward the jaw unlocking position.

13. In a chuck, a housing, a draw sleeve mounted for axial movement andchuck jaws mounted for radial movement therein, a driving connectionbetween them whereby axial movement of the draw sleeve causes radialmovement of the jaws, locking means within the housing movable inconsonance with the jaws and draw sleeve adapted automatically toprevent centrifugal movement of the jaws, means responsive to drawsleeve movement in clutch opening position for disengaging the lockingmeans during such movement to permit centrifugal movement of the jaws,said locking means offering no resistance to centripetal jaw movement.

HARRY L. PROCTOR.

REFERENCES CITED UNITED STATES PATENTS Name Date Hopkins May '7, 1929Number

